1. Field of the Invention
The present invention relates to a gas lighter burner having a porous throttle disc and a mechanism which exploits the temperature-related alteration in length of said mechanism for the maintenance by said throttle disc of a constant gas flow in spite of changes in temperature.
2. Description of the Prior Art
In the field of gas fueled lighters, there exists a problem with respect to varying flame height which results from pressure variations involved with the heating up of the fuel gas during use. This problem is discussed in connection with a prior art gas lighter burner disclosed in U.S. Pat. No. 2,620,643 to Nissen, dated Dec. 9, 1952. In the Nissen patent, a gas flow regulator of plastic in the shape of an upright cylinder is situated between a brass valve seating device and a connection piece of porous, sintered metal or porous china. According to this patent, the regulation of the quantity of gas theoretically occurs by means of the greater or lesser distance between the upper end surface of the cylinder and the smooth lower surface of the valve seating device. It should be understood that the temperature compensating regulation occurs between the valve seating device of brass and the porous sintered or ceramic block piece.
There is a considerable disadvantage in this prior art arrangement in that only vaporous gas can be regulated but not the liquid within the lighter. It is stated in the Nissen patent that if suitable dimensions are selected, a flame height can be achieved which is not dependent on temperature.
Mathematically expressed, the distance between the gas flow regulator and the valve seating device varies on the basis of an elongation coefficient of brass and plastic by 0.0054 mm at a change in temperature of 10.degree. C. For a flame 40 mm in height, assuming the customary valve seating bore of 0.3 mm diameter, a medium distance of approximately 0.004 mm is required. With this arrangement it is obvious that only in theory can the desired independence of temperature be achieved.
The prior art arrangement of Nissen, which appears workable on paper, is, however, virtually inoperative. If fine screw threads are applied to the block piece or to the thread insert piece, a pitch of 0.25 mm per turn is achieved. An alteration in the distance amounting to 0.004 mm thus requires an angle of rotation of 5.8.degree., which is for all practical purposes unobtainable, while the utilization of micro-screw threads in a lighter cannot be justified by virtue of the production problems and the costs involved.